/* Copyright 2018 Jason Williams (Wilba)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "is31fl3218.h"
#include "i2c_master.h"

// This is the full 8-bit address
#define ISSI_ADDRESS 0b10101000

// These are the register addresses
#define ISSI_REG_SHUTDOWN 0x00
#define ISSI_REG_PWM 0x01
#define ISSI_REG_CONTROL 0x13
#define ISSI_REG_UPDATE 0x16
#define ISSI_REG_RESET 0x17

// Default timeout if no I2C response
#define ISSI_TIMEOUT 100

// Reusable buffer for transfers
uint8_t g_twi_transfer_buffer[20];

// IS31FL3218 has 18 PWM outputs and a fixed I2C address, so no chaining.
// If used as RGB LED driver, LEDs are assigned RGB,RGB,RGB,RGB,RGB,RGB
uint8_t g_pwm_buffer[18];
bool g_pwm_buffer_update_required = false;

void IS31FL3218_write_register( uint8_t reg, uint8_t data )
{
	g_twi_transfer_buffer[0] = reg;
	g_twi_transfer_buffer[1] = data;
	i2c_transmit( ISSI_ADDRESS, g_twi_transfer_buffer, 2, ISSI_TIMEOUT);
}

void IS31FL3218_write_pwm_buffer( uint8_t *pwm_buffer )
{
	g_twi_transfer_buffer[0] = ISSI_REG_PWM;
	for ( int i=0; i<18; i++ ) {
		g_twi_transfer_buffer[1+i] = pwm_buffer[i];
	}
	
	i2c_transmit( ISSI_ADDRESS, g_twi_transfer_buffer, 19, ISSI_TIMEOUT);
}

void IS31FL3218_init(void)
{
	// In case we ever want to reinitialize (?)
	IS31FL3218_write_register( ISSI_REG_RESET, 0x00 );
	
	// Turn off software shutdown
	IS31FL3218_write_register( ISSI_REG_SHUTDOWN, 0x01 );

	// Set all PWM values to zero
	for ( uint8_t i = 0; i < 18; i++ ) {
		IS31FL3218_write_register( ISSI_REG_PWM+i, 0x00 );
	}
	
	// Enable all channels
	for ( uint8_t i = 0; i < 3; i++ ) {
		IS31FL3218_write_register( ISSI_REG_CONTROL+i, 0b00111111 );
	}
	
	// Load PWM registers and LED Control register data
	IS31FL3218_write_register( ISSI_REG_UPDATE, 0x01 );
}

void IS31FL3218_set_color( int index, uint8_t red, uint8_t green, uint8_t blue )
{
	g_pwm_buffer[index * 3 + 0] = red;
	g_pwm_buffer[index * 3 + 1] = green;
	g_pwm_buffer[index * 3 + 2] = blue;
	g_pwm_buffer_update_required = true;
}

void IS31FL3218_set_color_all( uint8_t red, uint8_t green, uint8_t blue )
{
	for ( int i = 0; i < 6; i++ ) {
		IS31FL3218_set_color( i, red, green, blue );
	}
}

void IS31FL3218_update_pwm_buffers(void)
{
	if ( g_pwm_buffer_update_required ) {
		IS31FL3218_write_pwm_buffer( g_pwm_buffer );
		// Load PWM registers and LED Control register data
		IS31FL3218_write_register( ISSI_REG_UPDATE, 0x01 );
	}
	g_pwm_buffer_update_required = false;
}
